There’s a few posts on AFF about the procedure for arriving at TBIT and then getting to other terminals at LAX, and how long it may take (number of flights arriving at that time, CBP, etc, etc). Some have experienced a smooth transfer while others have experienced delays. I plan on 4 hours, but it can be much less.
Although, there’s nothing quite like the adrenaline rush of not knowing if the doors will have already closed as you arrive at the gate for the connecting flight. Doors will often close 10 minutes before the scheduled departure time. Maybe a good idea to be wearing running shoes just in case.
If both flights are on the same PNR, then at least you are “protected”, so you will get the next ‘available’ flight (i.e., where seats are available), although I’m not sure of the frequency of WS flights LAX-LAS.